As forms of a network in which a base station and a radio communication terminal are connected with each other or radio communication terminals are connected with each other, there have been a form of connection with a single radio line (link) and a form of connection via a plurality of radio lines in related art. Communication by the form of connection with a single radio line (link) is referred to as single-hop communication or one-hop communication because the number of radio lines (the number of hops) through which data travels until the data reaches a destination is one. On the other hand, communication by the form of connection via a plurality of radio lines is referred to as multi-hop communication because a plurality of hops are used among terminals. Of the single-hop communication and the multi-hop communication, the multi-hop communication is employed in ad-hoc network which enables direct communication among radio communication terminals via no base station or no access point. In the ad-hoc network, other radio communication terminals having a relaying function are interposed between a terminal of a data transmission source and a terminal of a data transmission destination and data is relayed on a plurality of radio lines so as to expand a communication area. Accordingly, extensive radio network can be established.
In the multi-hop communication such as the above-mentioned adhoc network, a plurality of routes coexist in transmission/reception of data such as a packet. Accordingly, when a communication state of a route is deteriorated due to some kind of causes, the route can be changed into a new route of which the communication state is better than the prior route. However, a radio communication terminal which is a transmission source of a packet has to regularly transmit/receive a plurality of packets including detailed link information to and from other terminals in the same network, so as to select a route optimum for the radio communication terminal. There has been such problem that throughput in the network is degraded due to this packet communication. Such problem becomes noticeable when route change is frequently performed due to movement of a terminal or change of a communication environment and the communication amount of packets for a route change procedure is consequently increased.
Japanese Laid-open Patent Publication No. 2008-278148, International Publication Pamphlet No. WO 2008/035600, and Japanese Laid-open Patent Publication No. 2006-157117 are examples of related art.